An irregular z-line can be caused by gastroesophageal reflux disease (GERD), according to HealthTap doctors. Variation in the z-line can be normal as well, because the z-line varies from person to person.
GERD occurs when the acidic contents of the stomach back up into the esophagus, causing damage, notes MedicineNet. There are a variety of causes for this condition, including an abnormal lower esophageal sphincter, a hiatal hernia, abnormal esophageal contractions, and slow emptying of the stomach. GERD is rarely caused by abnormally large amounts of acid in the stomach.
GERD can cause more serious conditions, such as ulcers of the esophagus, Barrett's esophagus, and cough and asthma if complications occur due to esophageal damage, states MedicineNet. Usually, the condition does not cause damage or inflammation and only creates symptoms such as heartburn, regurgitation and nausea. However, if an ulcer develops, it can erode the esophageal blood vessels and cause severe bleeding.
GERD can be evaluated and diagnosed by a variety of methods, including an endoscopy, a biopsy, an X-ray, an examination of the throat and larynx, and a trial of treatment, explains MedicineNet. Treatment for the condition includes lifestyle changes, such as elevation of the upper body at night, and diet changes, such as avoiding alcohol, chocolate and caffeinated drinks.